soc: ti: pm33xx: Add base cpuidle support

Some cpuidle C-states supported on am335x and am437x, like C1 on am335x,
require the use of the wkup_m3_ipc driver, and all C-states beyond C0 on
both platforms require the use of the SRAM sleep code.

Pass am33xx_do_sram_idle as the idle function to the platform pm core to
be used by the cpuidle-arm driver when entering cpuidle states.
am33xx_do_sram_idle will detect when the wkup_m3 is needed and ping it
if necessary before calling the final cpu_suspend op which will execute
the SRAM code to put the cpu into idle.

Finally, use the begin_suspend and finish_suspend platform ops to be
called at the beginning and end of suspend path to allow use of
cpu_idle_poll_ctrl.

This prevents races between cpuidle and suspend paths trying to
communicate with the wkup_m3, as during suspend we only want it
configured for entry to suspend.

Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>

diff --git a/drivers/soc/ti/pm33xx.c b/drivers/soc/ti/pm33xx.c
index 19bdcac..de0123e 100644 (file)
--- a/drivers/soc/ti/pm33xx.c
+++ b/drivers/soc/ti/pm33xx.c
@@ -130,6 +130,19 @@ static int am33xx_push_sram_idle(void)
        return 0;
 }
 
+static int am33xx_do_sram_idle(u32 wfi_flags)
+{
+       int ret = 0;
+
+       if (!m3_ipc || !pm_ops)
+               return 0;
+
+       if (wfi_flags & WFI_FLAG_WAKE_M3)
+               ret = m3_ipc->ops->prepare_low_power(m3_ipc, WKUP_M3_IDLE);
+
+       return pm_ops->cpu_suspend(am33xx_do_wfi_sram, wfi_flags);
+}
+
 static int __init am43xx_map_gic(void)
 {
        gic_dist_base = ioremap(AM43XX_GIC_DIST_BASE, SZ_4K);
@@ -260,6 +273,8 @@ static int am33xx_pm_begin(suspend_state_t state)
                rtc_only_idle = 0;
        }
 
+       pm_ops->begin_suspend();
+
        switch (state) {
        case PM_SUSPEND_MEM:
                ret = m3_ipc->ops->prepare_low_power(m3_ipc, WKUP_M3_DEEPSLEEP);
@@ -301,6 +316,8 @@ static void am33xx_pm_end(void)
        }
 
        rtc_only_idle = 0;
+
+       pm_ops->finish_suspend();
 }
 
 static int am33xx_pm_valid(suspend_state_t state)
@@ -503,7 +520,7 @@ static int am33xx_pm_probe(struct platform_device *pdev)
        suspend_wfi_flags |= WFI_FLAG_WAKE_M3;
 #endif /* CONFIG_SUSPEND */
 
-       ret = pm_ops->init(NULL);
+       ret = pm_ops->init(am33xx_do_sram_idle);
        if (ret) {
                dev_err(dev, "Unable to call core pm init!\n");
                ret = -ENODEV;
@@ -522,6 +539,8 @@ err_free_sram:
 
 static int am33xx_pm_remove(struct platform_device *pdev)
 {
+       if (pm_ops->deinit)
+               pm_ops->deinit();
        suspend_set_ops(NULL);
        wkup_m3_ipc_put(m3_ipc);
        am33xx_pm_free_sram();